Electric switch



B. O. AUSTIN ELECTRIC SWITCH Nov. 10, 1936.

Filed April 14, 1934 A INVENTOR MCI/f)? Qiuf/n.

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Patented Nov. 10, 1936 UNITED STATES PATENT OFFICE ELECTRIC SWITCHPennsylvania Application April 14, 1934, Serial No. 720,611

'2 Claims.

My invention relates, generally, to electric switches, and moreparticularly to switches of the electro-magnetic type wherein thecontact members are actuated by electro-magnets.

An object of my invention, generally stated, is to provide an electricswitch which shall be simple and efllcient in operation and which may beeconomically manufactured and installed.

A more specific object of my invention is to increase the speed ofoperation of an automatic electric switch under overload orshort-circuit conditions.

Another object of my invention is to provide a quick acting overloadtrip mechanism for an electric switch.

Other objects of my invention will be either explained fully hereinafteror will be apparent to those skilled in the art.

In accordance with one embodiment of my invention, the moving contactarm of a switch is operated. by the over-load trip mechanism with outmoving the main armature of the switch, thereby quickly opening thecontact members by actuating the parts of the switch having a minimumweight.

For a fuller understanding of the nature and objects of my invention,reference may be had to the following detailed description taken inconjunction with the accompanying drawing, in which:

Figure 1 is a view, in side elevation of an electro-magnetic switchembodying my invention;

Fig. 2 is a view, in side elevation, of the switch illustrated in Fig. 1showing the position to which the movable contact member of the switchis actuated by the overload-trip mechanism, and

Fig. 3 is a diagrammatic view illustrating the manner in which theswitch may be connected in an electric circuit.

Referring now to the drawing, and particularly to Figs. 1 and 2, theswitch which is illustrated comprises a main operating magnet l and anoverload-trip magnet ll, both of which are mounted on an insulating base12. The magnet is provided with an energizing coil l3, a core I 4 and anarmature member l5 that is pivotally mounted on the frame l6 of theswitch by a pin l1.

As shown, the overload-trip magnet I I comprises a series or operatingcoil l8 and a holding coil l9, both disposed on one leg of a U-shapedmember 2|. The magnet II is provided with an armature member 22, alsopivotally mounted at H, which is actuated to the trip position shown inFig. 2 when a. predetermined value of current flows through the seriescoil l8. The holding coil l9 will retain the armature 22 in the positionshown in Fig. 2 after it has been raised to that position by the seriescoil l8.

The main armature carries a movable contact member 23 that is disposedto engage a fixed contact member 24 when the armature is actuated to theposition shown in Fig. 1 by the operating magnet ID. The contact member23 is mounted on a contact-carrying arm 25 which is pivotally mounted onthe armature l5 by a pin 26. A spring 21 is provided for resilientlypressing the movable contact member 23 against the fixed contact member24.

In order that the contact members of the switch shall be opened quicklywhen the current in the overload coil l8 exceeds a predetermined value,the contact-carrying arm 25 is so connected to the downwardly extendingarm 3| of the armature 22 by a link 32 that the contact-carrying arm 25is actuated about its pivot point 26 to open the contact members whenthe armature 22 is raised to the position shown in Fig. 2. Afterthecontact members have been partially opened by the overload-tripmechanism in the foregoing manner, the main operating magnet 10 isdeenergized and the main armature I5 is permitted to drop to itslowermost position, thereby further opening the contact members of theswitch.

In this manner the contact member 23 is disengaged ;from the contactmember 24 without moving the main armature I5, thereby providing a meansfor interrupting the circuit through the contact members by operatingthe parts of the switch having a minimum weight, which makes it possibleto greatly reduce the time required to open the contact members andinterrupt the circuit. The opening speed of the switch under overload orshort-circuit conditions is fast enough to limit the peak current, thusreducing the damage to other equipment that may be connected in thecircuit controlled by the switch.

As shown in Fig. 3, the switch herein described may be utilized as aline switch to connect a propelling motor of an electric vehicle to atrolley conductor 4|, the series coil l8 of the overloadtrip magnet llbeing connected in the motor circuit when the contact members 23 and 24of the switch are closed. The energizing coil l3 of the operating magnet10 is energized through a contact segment 42, which may be on the mastercontroller and an interlock member 43 which is actuated by theoverload-trip mechanism.

As described hereinbefore, the series coil ill will operate theoverload-trip mechanism to partially open the contact members of theswitch when the current flowing through the 'coil exceeds apredetermined value. When the overload-trip mechanism is operated by theseries coil II, the interlock ll is actuated to interrupt the circuitthrough the main magnet coil II and to establish a circuit through theholding coil ll, thereby energizing the holding coil to retain thearmature 12 in its uppermost position until the controller segment 42 isactuated to reset the overload-trip mechanism, after which the operatingmagnet coil I! may be energized to reclose the contact members of theswitch.

From the foregoing description, it is apparent that I have provided asimple and quick acting overload-trip mechanism which may be readilyapplied to any switch of a type having a pivoted contact-carrying arm,such as the electro-magnetic switch shown in the drawing or apneumatically-operated switch oi a type well known in the art.

Since numerous changes may be made in the above-described constructionand difierent embodiments of the invention may be made without departingfrom the spirit and scope thereof, it is intended that all mattercontained in the above description or shown in the accompanying drawingshall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. In an electric switch, in combination, a fixed contact member, amovable contact member disposed to engage the fixed contact member, apivotally-mounted contact arm for supporting the movable contact member,means for actuating the movable contact member into engagement with thefixed contact member, and means (or opening said contact members to anintermediate position between their fully open and fully closedpositions independently oi! the last named means.

2. In an electric switch, in combination, a fixed contact member, amovable contact member disposed to engage the fixed contact member, apivotally-mounted contact arm for supporting the movable contact member,means for actuating the movable contact member into engagement with thefixed contact member, and means for actuating the contact arm about itspivot point to open said contact members to an intermediate positionbetween their fully open and fully closed positions independently of thelast named means.

3. In an electric switch, in combination a fixed contact member, amovable contact member disposed to engage the fixed contact member, apivotally-mounted contact arm for supporting the movable contact member,means for actuating the movable contact member into engagement with thefixed contact member, and. means responsive to a predeterminedvalue ofcurrent for actuating the contact arm about its pivot contact member. amovable contact member diaposed to engage the fixed contact member, apivotally-mounted contact arm for supporting the movable contact member,operating means for actuating the movable contact member into engagementwith the fixed contact member, and electro-magnetic means responsive toa predetermined value of current for actuating the contact arm about itspivot point to open said contact members to an intermediate positionbetween their fully open and iully closed positions independently of theoperating means.

5. In an electric switch, in combination, a fixed contact member, amovable contact member disposed to engage the fixed contact member, apivotally-mounted contact arm for supporting the movable contact member,electro-magnetic operating means for actuating the movable contactmember into engagement with the fixed contact member, and an overloaddevice responsive to a predetermined value of current for actuating thecontact arm about its pivot point to open said contact members to anintermediate position between their fully open and fully closedpositions independently of the electro-magnetic operating means.

6. In an ,electric switch, in combination, a fixed contact. member, amovable contact member disposed to engage the fixed contact member, apivotally-mounted contact arm (or supporting the movable contact member,electro-magnetic operating means for actuating the movable contactmember into engagement with the fixed contact member, and anelectro-magnetic overload device having an armature member for actuatingthe contact arm about its pivot point to open said contact members to anintermediate position between their fully open and fully closedpositions independently of the electro-magnetie operating means.

7. The combination with an electric switch having a pivotally-mountedcontact arm for supporting a movable contact member and operating meansfor actuating the movable contact member into engagement with a fixedcontact member, of an electro-magnet having a pivotallymounted armaturedisposed to actuate said contact arm about its pivot point to open saidcontact members to an intermediate position between their fully open andfully closed positions independently of said operating means when theelectro-magnet is energized by a predetermined value oi! current.

BASCUM O. AUSTIN.

